1. Field
The described technology relates generally to a rechargeable battery.
2. Description of the Related Art
Unlike a primary battery, a rechargeable battery iteratively performs charging and discharging. A rechargeable battery having low capacity is used in a portable small electronic device such as a mobile phone, a laptop computer, and a camcorder, while a battery having large capacity is widely used as a power source for driving the motor in a hybrid vehicle, and the like.
The rechargeable battery includes an electrode assembly having a positive electrode and a negative electrode provided on respective sides of a separator, a casing to house the electrode assembly, a cap plate to close and seal the opening of the casing, and electrode terminals electrically connected to the electrode assembly and configured to penetrate the cap plate.
When a conductor (e.g., a conductive element) penetrates the case of the rechargeable battery, and thus contacts or pokes the electrode assembly, the negative electrode and the positive electrode may be short-circuited in the electrode assembly, thereby causing ignition or explosion of the electrode assembly.
To avoid or prevent ignition or explosion of the electrode assembly, the case may be connected to the positive electrode, and a safety member, which is connected to the negative electrode, is provided between the case and the electrode assembly. When the conductor penetrates the case and thus contacts the safety member, a high-voltage current output to the electrode assembly is discharged while flowing to the electrode assembly through the cap plate, the case, and the conductor. However, because the safety member has a constant thickness, the safety member has low electrical resistance (e.g., current resistance). Therefore, when the conductor penetrating the case contacts the safety member, an over-current flows in a contact area where the safety member and the case contact each other.
Accordingly, due to the over-current, the safety member may melt at the contact area. When the safety member melts, the current charged in the electrode assembly is no longer discharged. However, when the conductor moves further into the electrode assembly in this condition, the electrode assembly may still ignite or explode due to a short circuit between the negative electrode and the positive electrode in the electrode assembly.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.